It seems to me that you have to check your coil/points/leads. A shitty coil will either give you no spark or an orange dirty spark, one way to check it would be a resistance test, do you have a multimeter?
Resistance test as well for the leads.
Check if your points are opening and closing, get the back wheel up, put it in the highest gear, and rotate the back wheel while looking at the points.
I dunno what else.
Quite sound advice but, if you are running shitty old plug leads, pull the spark plug caps off and hold the lead about 5mm off the head (keeping clear of the spark plug hole) and give it a kick, if it sparks, the plug caps are buggered, I take it that you have no spark at all, with that I mean on both cyclinders?
OK done all that now go and check points, condensers etc....
Mmick